n | a(n) |
---|---|
1 | 0 |
2 | 4 |
3 | 16 |
4 | 91 |
5 | 459 |
6 | 2429 |
7 | 12678 |
8 | 66380 |
9 | 347305 |
10 | 1817234 |
11 | 9509123 |
12 | 49756006 |
13 | 260353922 |
14 | 1362310931 |
15 | 7128385902 |
16 | 37299670925 |
17 | 195172780250 |
18 | 1021252966367 |
19 | 5343766480365 |
20 | 27961572573739 |
21 | 146310575925354 |
22 | 765578706008096 |
[0,4,16,91,459,2429,12678,66380,347305,1817234, 9509123,49756006,260353922,1362310931,7128385902, 37299670925,195172780250,1021252966367, 5343766480365,27961572573739,146310575925354, 765578706008096] |